This invention pertains to the field of Hall sensors intended for the quantitative measurement of magnetic fields.
The general principle of Hall effect sensors is well known. In particular, sensors are known which are constituted by a multilayer structure comprising a thin layer of a semiconductor material deposited on a substrate which is itself a semiconductor, with the two layers being electrically isolated from each other.
As an example, European patent EP 572,298 describes a xe2x80x9ctwo-dimensional electron gasxe2x80x9d Hall effect sensor comprising, on an isolating substrate, a quantum well structure, a carrier supply layer adjacent to the quantum well structure, of a thickness less than 250 angstroms and possessing a surface density of donors integrated over the entire surface of the supply layer of carriers lower than a threshold value, an isolating burial layer deposited on the carrier supply layer, possessing an energy conduction band greater than the fermi energy of the sensor and of a thickness greater than 200 angstroms.
European patent EP 458,466 describes a Hall effect device comprising a substrate, an active layer formed by a diamond semiconductor deposited on the substrate, a pair of electrodes deposited on the opposite sides of the active layer, for introducing a current in the active layer in one direction and another pair of electrodes deposited on the other opposite sides of the active layer for detecting a tension or a tension component which is induced in a direction which is generally orthogonal to the direction of the current.
U.S. Pat. No. 5,536,953 describes a broad-band semiconductor comprising multiple dopants at low concentrations.
The problem that characterizes the sensors according to the prior art is that of the operating domain. In fact, the metrological performances of the sensors according to the prior art degrade (decrease in sensitivity, nonlinearity, etc.) at temperatures higher than 200xc2x0 C. This degradation is linked to the performance of the structure (deficiencies in the electric isolation of the active/substrate layer) and/or the active layer (change in the conduction mechanisms, etc.).
It would therefore be advantageous to provide a Hall effect sensor exhibiting low sensitivity to temperature, typically of less than 250 ppm/xc2x0 C. for operating temperatures greater than 200xc2x0 C., and having a high Hall KH coefficient on the order of several hundreds of volt/ampere/tesla. KH is inversely proportional to the surface carrier density and the electron charge.
This invention relates to a Hall effect sensor formed in a multilayer structure including a thin active layer deposited on a substrate, wherein the substrate is an insulating, semi-insulating or semiconductor material of type pxe2x88x92 or n+, respectively, to electrically isolate the active layer of the substrate and wherein the active layer is a weakly doped semiconductor material of type nxe2x88x92 or pxe2x88x92 in an exhaustion regime.
This invention also relates to the above Hall effect sensor, further including a bar having a body extended by two pairs of lateral arms, with the body having at each of end portions thereof an electrode for electric power, two opposed lateral arms including electrodes for acquisition of a Hall signal and two adjacent arms having electrodes for measuring resistance.